My gas furnace won't fire up. It triggers the induced draft motor, which runs for about 20-30 seconds, and then the whole system shuts down. Up until yesterday it was working fine and I had been running it for a couple weeks now (in Minnesota). The only thing that changed was that yesterday I was going round the house and sealing up all the penetrations, and I blew some Great Stuff around the exhaust vent. I've checked the vent and no foam got in the pipe/vent, and none even came through to the inside side of the joists. It all just went behind the vinyl receptacle cover and AROUND the vent. There is a little condensation around the inside of the pvc pipe, but I'm not sure if this is increased from before I added the Great Stuff (I never looked that closely before). [attach]110822[/attach] This is a horizontal concentric termination. I'm getting error code "45"which is : low pressure switch is open. Possible issues: -insufficient combustion airflow -insufficient combustion air -improper pressure switch setting I'm not sure how adding spray foam AROUND the exhaust changed anything. Other that scraping out all the spray foam, is there something else I should correct or look at? Can you guys help a single girl out??Thank you very much! -L

I've had an oil furnace before so I know how to bleed the line when I mess up and run out of oil. So we ran out Friday and no one can deliver until I sign up with someone and of course all businesses are closed. On advice we were told to hold us over we could use diesel fuel. We got 10 gallons and bled the line and it seemed to work them about 20 mins later or shut off and now when I tried to bleed the line its just bubbling and sputtering no clean fuel push. What can I do, other than cry...did that already.